AFM 2-4

Lynx M

Unmanned Aircraft System

Aircraft Flight Manual 

SwiftRadioplanes.com
AFM 2-4

Record of Revisions

AFM 1-1 14 April 2013

AFM 1-2 27 July 2013

AFM 1-3 20 July 2014

AFM 1-4 16 September 2014

AFM 2-1 16 January 2015

AFM 2-2 28 February 2015

AFM 2-3 08 March 2015

AFM 2-4 21 April 2015
AFM 2-4

Table of Contents

Section 1: General Information and System Description..............1

Airframe ....................................................................................................................................................1

Flight Control Surfaces..............................................................................................................................1

Propulsion System.....................................................................................................................................2

Takeoff and Landing..................................................................................................................................2

Avionics.....................................................................................................................................................2

Crew Members..........................................................................................................................................2

Communications Equipment.....................................................................................................................2

Navigation Control ....................................................................................................................................2

User Interfaces..........................................................................................................................................3

Information Displays.................................................................................................................................3

Safety Devices and Fail-safes....................................................................................................................3

Throttle safety key ................................................................................................................................3

Battery Monitor ....................................................................................................................................3

Manual Control .....................................................................................................................................4

Low Voltage Cutoff and Current Limiter...............................................................................................4

Flight Termination System (FTS) ...........................................................................................................4

Fail-safes ...............................................................................................................................................4

GCS Alerts..............................................................................................................................................4

Section 2: Performance and System Limitations .........................5

Prohibited Maneuvers: .............................................................................................................................5

Section 3: Getting Started ........................................................6

Download Applications.............................................................................................................................6

Mission Planner (GCS)...........................................................................................................................6

SwiftTag (Photo Geo-Tagging) ..............................................................................................................6

Install Mission Planner..............................................................................................................................6

Verify Telemetry Radio Driver Installation................................................................................................6

How to Determine Telemetry Radio COM Port........................................................................................6

Initial Mission Planner Configuration........................................................................................................7
AFM 2-4

SwiftTag Configuration..............................................................................................................................8

Understanding The Handheld Transmitter...............................................................................................8

Switch Positions....................................................................................................................................8

Changing Autopilot Modes ...................................................................................................................9

Powering On........................................................................................................................................10

Transmitter Battery Status..................................................................................................................10

Updating the Autopilot Firmware...........................................................................................................10

Section 4: Normal Procedures.................................................11

Preflight Part 1: Aircraft Inspection ........................................................................................................11

Aircraft Preflight Inspections ..............................................................................................................11

Aircraft Power On ...............................................................................................................................14

Preflight Part 2: GCS Checks....................................................................................................................15

GCS Power On .....................................................................................................................................15

Flight Data Screen ...............................................................................................................................16

Initial Setup Screen .............................................................................................................................17

Flight Planning Screen.........................................................................................................................18

Flight Data Screen ...............................................................................................................................22

Preflight Part 3: System Checks ..............................................................................................................23

Takeoff ....................................................................................................................................................26

Manual Takeoff...................................................................................................................................27

Auto Takeoff........................................................................................................................................28

Landing....................................................................................................................................................28

Deep-Stall Landing ..............................................................................................................................29

Belly Landing .......................................................................................................................................30

Post Flight................................................................................................................................................31

Photo Tagging .........................................................................................................................................31

Battery Charging .....................................................................................................................................34

Section 5: Emergency Procedures ...........................................36

Motor Failure Below 30 meters AGL...................................................................................................36

Motor Failure Above 30 meters AGL ..................................................................................................36

Uncontrolled Flight .............................................................................................................................37

Safety Pilot Low Battery......................................................................................................................37
AFM 2-4

Safety Pilot Uplink Failure...................................................................................................................38

GPS Failure ..........................................................................................................................................38

GCS Low Battery..................................................................................................................................38

GCS Telemetry Fail ..............................................................................................................................39

Deep-Stall Abort..................................................................................................................................40

Section 6: Repair Instructions.................................................42

List of Common Replacement Hardware................................................................................................42

Replacing a Propeller ..............................................................................................................................43

Replacing a Broken Wing Bolt.................................................................................................................43

Replacing a Tail Clip ................................................................................................................................44

Replacing a Stabilator Arm......................................................................................................................45

Replacing the Motor ...............................................................................................................................46

Replacing a Servo....................................................................................................................................48

Replacing a Skid Pad ...............................................................................................................................49

Repairing Wing Delamination .................................................................................................................50

Re-Binding the DX7s Transmitter............................................................................................................52

Appendix I............................................................................53

ESC Beep Codes.......................................................................................................................................53

Appendix II...........................................................................54

Battery Cell Discharge Curve...................................................................................................................54

Appendix III..........................................................................55

Lynx M PWM/PPM Wiring Diagram........................................................................................................55

Appendix IV ..........................................................................56

Downloading Autopilot Logs...................................................................................................................56
1

Section 1: General Information and 

System Description

Lynx is a fixed-wing, electric, Unmanned Aerial System (UAS) designed for aerial imagery collection and research. It 

is made from durable foam and Kevlar to withstand field use and hard landings. Lynx consists of six main parts:

 A removable three-piece wing

 The fuselage

 A removable stabilator (elevator)

 A swappable camera module

 The autopilot, to include radios and sensors

Airframe

The Lynx airframe weights 2 kg without battery or payload and has a 2.3 meter wingspan. The fuselage, wings, and 

stabilator are constructed with Kevlar over a foam core. Foam skid pads are fitted beneath the fuselage to absorb 

energy for deep-stall landings. The main airframe components are assembled without tools. Spare parts and 

subcomponents can be replaced in the field using basic tools, supplied with each tool kit.

Flight Control Surfaces

Lynx uses two control surfaces: a rudder and stabilator. The Rudder is a vertical control surface used to roll the 

airframe left and right in order to turn the aircraft to a desired heading. The stabilator is used to pitch the airframe 

up and down in order to climb or descend to a desired altitude. For the deep-stall landing, the stabilator will 

deflect upward, beyond what is used for navigation, to induce the stall. Both control surfaces are actuated by servo 

motors.
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Propulsion System

The propulsion system consists of the flight battery, brushless motor, electronic speed controller (ESC), and 

propeller assembly. The propeller folds back to prevent damage upon landing and for transport. Lynx uses a high 

density, rechargeable Lithium Polymer (LiPo) battery. The battery pack consists of 12 cells wired in a 6 series/2 

parallel configuration (6S2P). The result is an 11,000 milliampere-hour (mAh) 6 cell battery. Operating voltage is 

19.8 to 25.2 volts.

Takeoff and Landing

Lynx is hand-launched and recovered using either a deep-stall or belly land. A deep-stall is a near-vertical, stable 

descent caused by deflecting the stabilator upward. During the descent, throttle is set to 0 and pitch is locked at 

the deep-stall angle. Lynx is steerable during the descent and the process can be aborted in flight.

To minimize damage from a hard landing or deep-stall, the wings and stabilator are designed to separate from the 

fuselage. In extraordinary landings, certain parts are designed to break: these parts can be swapped in the field 

with simple tools. Spares of breakaway parts are included with each system.

Avionics

Lynx uses the Pixhawk autopilot, advanced autopilot system designed by the PX4 open-hardware project and 

manufactured by 3D Robotics. It features advanced processor and sensor technology and a NuttX real-time 

operating system, delivering incredible performance, flexibility, and reliability. The autopilot kit contains the 

following sensors:

 3-axis gyroscope

 3-axis accelerometer / magnetometer

 3-axis accelerometer / gyroscope

 Barometer

 Secondary 3-axis magnetometer

 Global Positioning System (GPS)

 Digital airspeed

Crew Members

Lynx is operated by a two person crew: a Safety Pilot (SP) and Aircraft Operator (AO). 

Communications Equipment

Lynx utilizes two control frequencies. The Safety Pilot’s controls are transmitted with a handheld transmitter on 

2.4 GHz. The Aircraft Operator utilizes a two-way data radio on 915 MHz to upload flight plans to the aircraft, 

monitor position and status, and configure the autopilot settings. 

Navigation Control

Lynx can be controlled in three ways: manually, autopilot assisted, or autopilot controlled. The Safety Pilot 

determines who is in control with a mode switch on the handheld transmitter. Manual control bypasses the 

autopilot and allows for full range of aircraft movement. Autopilot assisted modes are designed to help the pilot 

by limiting their pitch/roll angles and by stabilizing the aircraft when “hands-off.” Autopilot assisted modes 

include: stabilize and fly-by-wire. In autopilot controlled modes, the autopilot is navigating and the Aircraft 

Operator commands the aircraft via the Ground Control Station (GCS). Autopilot controlled modes include: loiter, 

guided, Return To Launch (RTL), and auto (mission). The Safety Pilot can manually override the autopilot in flight if 

needed.
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User Interfaces

The GCS software used by Lynx is Mission Planner. Mission Planner is the Aircraft Operator’s interface to the 

aircraft. Using the GCS, the AO configures the aircraft for flight, creates and uploads flight plan, and monitors 

aircraft position and status. Mission Planner can be installed on any laptop, desktop, or x86 tablet computer 

running Windows. 

Information Displays

Mission Planner has two main displays: a Heads-Up Display (HUD), and a moving map. The HUD displays aircraft 

information - such as warnings, airspeed, altitude, and attitude - overlaid on an artificial horizon. Users can 

configure other aircraft parameters to be displayed. The moving map displays the flight plan, waypoints, survey 

grid, aircraft position, heading, and ground track over a satellite map. Users can configure other aircraft 

parameters to be displayed.

Mission Planner GCS Display

Safety Devices and Fail-safes

Lynx is fitted with a variety of safety devices to protect crew members on the ground and the aircraft inflight.

Throttle safety key

The throttle safety protects against unwanted motor start-ups on the ground during preflight checks. The key, 

located on the left side of the fuselage, will not allow the motor to spin when inserted. This will stop throttle 

commands from both the Safety Pilot and autopilot. When the key is removed, a red light will illuminate on the 

side of the fuselage and the motor will emit an audible arming tone. The motor will only arm if throttle was zero 

before the key was removed.

Battery Monitor

The battery monitor displays the flight battery voltage and reports it to Mission Planner. This enables the AO to 

monitor aircraft battery voltage in flight and determine when to land.
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Manual Control

Lynx uses an external pass-through for manual control via a multiplexer. This allows the Safety Pilots inputs to 

bypass the autopilot hardware when flying manually.

Low Voltage Cutoff and Current Limiter

The Electronic Speed Controller has a low voltage cutoff and current limiter that prevents the flight battery from 

sustaining damage. 

Flight Termination System (FTS)

Lynx’s deep-stall landing also serves as a FTS for certain emergencies. The aircraft is fitted with energy absorbing 

skid pads on the underside of the fuselage that absorb impacts from deep-stalls and potential crashes.

Fail-safes

In flight, a Return To Launch (RTL) failsafe is triggered upon loss of Safety Pilot link. At which point, Lynx will fly to 

the nearest rally point or home location until link is reestablished. 

GCS Alerts

Mission Planner will visually display warnings for loss of telemetry link, low altitude, low battery voltage, bad 

attitude and heading reference system (AHRS), and bad GPS. Mission Planner can also be configured to announce 

voice alerts.
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Section 2: Performance and System 

Limitations

General

Wingspan 2.3 m

Propulsion Electric

Empty Weight 2.0 kg

Battery 1.3 kg

Payload .7 kg

Maximum Gross Takeoff Weight 4.0 kg

Center of Gravity Limits -6.0 to -9.5 cm (center wing leading edge datum)

Performance

Cruise Speed 16 m/s

Never Exceed Speed (VNE) 22 m/s

Stall Speed 9 m/s 

Endurance 180 min (with a5100 payload)

Range 1.5 km (approx.)

Takeoff

Takeoff Method Hand launch

Auto Takeoff Climb Angle 20 degrees

Distance to clear 18 meter obstacle 40 m (with 5 m/s headwind)

Distance to clear 50 meter obstacle 100 m (with 5 m/s headwind)

Landing

Landing Method Belly land or vertical deep-stall

Electrical

Low Battery Voltage 19.8 volts (3.3v per cell)

ESC Cutoff Voltage 18.0 volts (3.0v per cell)

Battery Charge Limit 1C 

Battery Discharge Limit 3C continuous, 6C burst (<15 seconds)

Safety Pilot Frequency 2.4 GHz

Telemetry Frequency 915 MHz

Environmental

Wind Limitation 8 m/s gusting to 12 m/s (15-25 knots)

Precipitation none

Prohibited Maneuvers:

 Launch or landing with any tailwind, including deep-stall

 Flight into known icing conditions

 Flight into visible moisture

 Flight beyond Safety Pilot’s visual line-of-sight (LOS)
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Section 3: Getting Started

This section explains how to install the required software on the GCS and the recommended configuration.

Download Applications

Mission Planner (GCS)

To find the current recommend version of Mission Planner that has been tested with the Lynx M, as well as a copy 

of this manual can be found on the FTP server. The server can be accessed at:

ftp://customerFiles.swiftradioplanes.com

User: customerFiles

Password: customerSwiftRP

Due to changes in functionality and bugs that can be introduced between versions, it is highly recommend staying

with the latest version of Mission Planner that has been tested by Swift Radioplanes.

SwiftTag (Photo Geo-Tagging)

Additionally you will need to download SwiftTag to geo-tag photos taken in flight. This can be downloaded from 

http://swiftradioplanes.com/swifttag/

Install Mission Planner

Install Mission Planner. During the installation, Mission Planner will ask you to install a series of drivers to enable 

the telemetry radio and USB connections to the autopilot. It is recommended to use the Mission Planner provided 

drivers.

Verify Telemetry Radio Driver Installation

Depending upon what version of Windows you have and your security settings, the drivers that Mission Planner 

installed may not work. To check that the drivers have installed correctly, attach the antenna to the telemetry 

radio, and then attach the telemetry radio to the computer via USB cable. Windows should automatically detect 

the radio and utilize the driver. If you receive a message saying that the driver is not digitally signed, or that 

windows could not find an appropriate driver, you can download and directly install the latest driver from 

http://www.ftdichip.com/Drivers/VCP.htm

How to Determine Telemetry Radio COM Port

After the driver has been installed and the radio is connected properly, it is worth determining what COM port the 

radio is on. With Mission Planner started and the radio connected, find the dropbox in the top right corner of the 

screen that says either “Auto” or is blank. This dropbox will open a list that should have one or more Com ports,

such as COM25 or COM4. If you then remove the radio from the computer and reopen the dropbox, one of the 

ports should have disappeared. This is the appropriate COM port to use for the radio. If you always reattach the 

radio to the same USB port the COM number should stay the same.
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The Com Port dropbox located in Mission Planner.

Initial Mission Planner Configuration

Within Mission Planner select the Config/Tuning tab at the top of the screen, then select Planner from the left 

menu.

The Planner Menu in Mission Planner.

First set the Distance Units to be meters and the Speed Units to be in meters per second (ms). This makes Mission 

Planner work in meters and meters per second for all screens. While it offers other units, this is not recommended 

due to internal rounding errors on converting units, and not all screens support other units.
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Next, if voice alerts are desired, check the Enable Speech checkbox. A row of checkboxes will show up. Select all 

the desired alerts. When you check a desired alert it will offer you a checkbox that allows you to change the 

content of the speech alert. The default text is fine, except on the battery warning. When asked what the warning 

should say, use “WARNING, Battery at {batv} Volt” set the warning voltage to 20.0, and the percentage to -1. A 

good starting set is to use the Waypoint, Mode, Battery Warning, Alt Warning, and Arm/Disarm alerts.

To save the changes you have made on this page simply select the Flight Data tab and all the changes should be 

saved. To verify this, restart Mission Planner and open the Config/Tuning tab again to verify settings.

Move back to the Flight Data tab and right click on the HUD, from the menu that opens select the checkbox for 

ch3percent, when asked for a prefix enter “Throttle: ” instead of the “ch3percent: ” You can then close the User 

Items menu.

SwiftTag Configuration

To install SwiftTag simply unzip the downloaded package and place the folder somewhere you can easily find it. 

You will need to be able to find this folder later when running the preflight. To run SwiftTag you will need Java 8 

installed which can be downloaded from https://www.java.com/en/download/windows_manual.jsp?locale-=en. If 

you are using the computer to fly with Mission Planner, and just need the sync script, then you can safely choose 

to not install java. 

Understanding The Handheld Transmitter

The handheld transmitter is used by the Safety Pilot to control Lynx. With the transmitter, Lynx can be flown 

manually or in an autopilot assisted mode such as stabilize. It also controls the autopilot mode and initiates the 

deep-stall.

Switch Positions

The following diagram applies to both the DX7s and DX8 model transmitters. Many switches are not used and the 

left stick (throttle) uses just one axis, up and down. The position of the unused switches is inconsequential.

Left Stick

The left stick controls throttle. Advance throttle by pushing the stick forward. When Lynx is in an autopilot 

controlled mode, the throttle position is inconsequential.
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Right Stick

The right stick controls pitch (elevator) and roll/heading (rudder). Pull the stick back to pitch up, push forward to 

pitch down. Push the stick right to roll right and vice versa.

Stopwatch/Bind

This press button acts as a stopwatch for timing flight duration. Press to start/stop.

2 Position Deep-stall Switch

Pull the switch towards you to deflect the stabilator upward and thus initiate a deep-stall.

3 Position Mode Switch

The bottom switch position (pulled towards you) is manual control. The middle position may be reserved for 

modes such as stabilize, fly by wire, and loiter if desired; typically these modes are not needed for a mission. The 

top position is auto (autopilot) control. Note, the position of the mode switch and what effect it has on the 

autopilot can be configured in Mission Planner, on the Initial Setup Screen under Flight Modes. If you change the 

autopilot flight modes, modes 2/3 and 4/5 must be paired and reflect the same (i.e. mode 4 and 5 would both be 

set to loiter).

Flight modes are found in Mission Planner under Initial Setup -> Flight Modes.

Changing Autopilot Modes

There are two ways to change autopilot modes: first with the mode switch on the handheld transmitter, and 

secondly in Mission Planner. The mode switch on the transmitter always takes precedence so that the Safety Pilot 

may override the autopilot if needed. If the transmitter is turned off, or if uplink is lost, the Return to Launch (RTL)

failsafe will take precedence over the mission.
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Switch Position Mode Switch 

(down)

Mode Switch

(middle) 

Mode Switch

(top)

Deep-Stall

Engaged

Transmitter 

Off

Flight Mode 6 5/4 3/2 n/a 1

Who’s in Control Safety Pilot AO AO Safety Pilot AO

Result Manual Control Autopilot Control Autopilot Control Manual Control RTL

Powering On

To power the handheld transmitter, slide the on/off switch to the right. The transmitter will boot and show the

Lynx tail number. To change models, turn on the transmitter while holding down the scroll wheel. At the System 

Setup screen, scroll down to Model Select and press down on the scroll wheel. Scroll through the list until you 

have found the correct model, select it by pressing down on the scroll wheel. Next press the back button to boot 

the transmitter.

Handheld transmitter display screen.

Transmitter Battery Status

4.3 volts for the stock NiMH battery is considered low voltage. 6.4 volts for the optional extended LiPo battery is 

considered low voltage. Draining past 6.4 volts may damage the LiPo pack.

Updating the Autopilot Firmware

Due to the large number of changes that can happen with an autopilot firmware, it is recommended to wait for a 

new release to be tested first. Any required changes in parameters will be noted with the parameter updates as 

well as any expected behavior changes. News of a new firmware or parameter change will be distributed with a 

mailing list. If you need to ensure you are on the mailing list or have questions please contact 

support@swiftradioplanes.com.
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Section 4: Normal Procedures

This is an expanded explanation of the procedures outlined in the Operator’s and Crewmember’s Checklist. This 

manual is intended to be used for training purposes, and the abbreviated checklist is to be used during flight 

operations. 

The lines of the Operator’s and Crewmember’s Checklist follow a standard format: Item-Action. It first states the 

object to be checked, then the action that is taken to ensure it is in the correct condition. 

The preflight takes place in three phases:

1. Aircraft Inspection- Hands-on inspection of the aircraft components.

2. GCS Preflight Checks- Checks and configuration of the autopilot.

3. Systems Checks- Physical tests of the aircrafts responses to GCS commands.

With experience, parts 1 and 2 may be performed concurrently by two personnel, and part 3 is performed by both 

personnel working together. 

Preflight Part 1: Aircraft Inspection

Aircraft Preflight Inspections

1. Fuselage - Inspect

Visually check the fuselage for any cracks or wrinkles in the Kevlar skin. Check the foam core for 

any major cracks or dents.

2. Wing Bolts - Present and Spaced

Check that all four wing bolts are installed. Set the correct gap using the supplied socket and 

spacing tool. Typically, unless a wing bolt was replaced after the previous flight, the bolts will not 

need spacing.

 

Left: Inspect the fuselage. Right: Ensure the wing bolts are properly spaced. 

3. Skid Pads - Inspect

Ensure both pads are adhered to the fuselage. Visually check for any major rips, dents, or missing 

pieces of foam. Normal wear and tear can be patched with gaffer’s tape. A pad will remain 

useable until large pieces of foam are missing.
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4. Propellers and Motor - Serviceable

Inspect the propeller assembly. Check each propeller blade for chips and cracks, and ensure they 

are securely mounted to the propeller hub. If the propeller blade moves fore and aft freely 

without resistance, tighten the mounting bolt until resistance is felt. The propeller blade should 

still be movable, such that on landing it can fold back, but fairly stiff to hold its position 

otherwise. Inspect the spinner and spinner mounting screw. Ensure the entire propeller assembly 

spins freely. Grasp the spinner and ensure that the propeller assembly and motor are rigidly 

mounted to the aircraft and that the propeller hub is not scraping the fuselage. Ensure all motor 

mounting hardware (4 motor screws, 4 bulkhead screws) is present and securely fastened.

5. Propeller - Extended and Clear

Ensure that propeller blades are extended and the propeller arc is clear. 

 

Left: The folding propellers fold back for landing and transport. Right: Ensure the propeller blades are extended and 

clear.

6. Pitot Tube - Inspect and Attach

Insert the pitot tube into its clip atop the rudder. Ensure that the hoses between the pitot tube 

and airspeed sensor are securely attached. The flexible tubing should not be kinked nor 

punctured. The pitot tube should point forward and parallel with the fuselage. 

Left: Click the pitot tube onto the rudder. Right: Ensure the pitot tube points straight and parallel with the fuselage.
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7. Servos - Check Movement and Linkages

Move each servo through its normal range of movement, feeling for any obstruction to 

movement. The gearing of the servo will normally provide light, steady resistance to movement. 

Any abrupt resistance to movement requires further inspection, as this may be indicative of a 

broken tooth in the servo. Check servo linkage arms, ball joints, and mounting hardware for 

security. 

Caution: Flying with a possibly broken servo may result in aircraft failure and loss.

8. Battery – Inspect and Install

Inspect the flight battery for any cuts, punctures, or gashes that expose individual cells. Do not fly 

a battery with exposed cells. Check the battery voltage using the handheld battery tester. Pack 

voltage should be approximately 25 volts. Using the Cell button, check the voltage of all six cells. 

A battery may be flown until voltage per cell has reached 3.3 volts, at which point the aircraft

should be landed immediately. If the difference between any two cells is greater than 0.1 volts, 

place the battery on the charger and run the balance function. Do not fly the battery until it is 

properly balanced. Typical spreads of a charged and balanced battery are less than 0.05 volts.

Secure the battery with the provided Velcro straps.

Note: The battery percentage (%) indicator on the handheld battery tester is not indicative of 

actual battery levels. Refer only to voltages.

Left: Insert the battery with the pull tab to the rear and fasten down it down with the Velcro straps. Right: Check 

the battery pack voltage, cell voltage, and spread prior to each flight using the handheld tester.

9. Stabilator - Inspect

Inspect the stabilator surface for cracks and wrinkles. Note that some wrinkling on the stabilator

is normal after repeated deep-stalls. Check the tail clips for cracks. Ensure the tail clips are rigidly 

mounted to the stabilator. Inspect the stabilator mounting hardware on the fuselage. Check that 

the mount points on the fuselage are present and secure, and that the carbon fiber stabilator 

arm is in serviceable condition. If the arm is bent or broken, replace it.
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10. Wings - Inspect 

Inspect the wings, looking for cracks, deformation, and delamination. Note that some wrinkling 

on the wings is normal after repeated deep-stalls. Inspect the center wing attachment for 

punctures. Ensure the embedded magnet is free of any ferrous dust or gravel sticking to the rib. 

Inspect the four carbon spar joiners “wishbones” for breaks and delamination. 

Caution: On windy days, secure the wings so that they cannot blow away. Failure to do so may 

result in wing damage. 

Note: The wings and stabilator are constructed from relatively soft foam that may dent if pinched 

or pressed into.

Aircraft Power On

1. Handheld Transmitter - On

Turn on the handheld transmitter. Ensure that the model selected matches the Lynx tail number.

2. Handheld Transmitter - Verify Manual

Ensure the three position mode switch on the transmitter is in manual 

Warning: Powering on the aircraft in any mode other than in manual can result in unexpected 

behavior such as inadvertent propeller startups, which can cause equipment damage and/or 

personnel injury.

3. Throttle Safety Key - Attach

Ensure the throttle safety key is inserted fully.

Warning: Failure to fully insert the throttle safety key may result in inadvertent propeller 

startups, which can cause equipment damage and/or personnel injury. The throttle safety key is 

intended as a secondary safety device. It is not intended to replace safe practices or careful 

handling of the Lynx UAS.

 

Left: Ensure the throttle safey key is fully inserted before powering on. Right: The red LED just above the key will 

illuminate when the key is removed and the motor is armed.
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4. Flight Battery - Connect

Ensure all personnel are clear of the propeller. Connect the battery. Observe autopilot status 

LED. The autopilot is initializing while the LED is flashing red and blue; avoid moving the aircraft

during this time. Ensure that the battery connector is fully seated. The motor should emit a tone. 

If no tones are heard, check the wires connected to the motor, located under the battery.

Caution: Excessive movement of the aircraft during the autopilot initialization can result in a poor 

startup calibration and may require power cycling.

Pixhawk LED Status

Flashing Red & Blue Initializing

Double Flashing Yellow Error. System refuses to arm

Flashing Blue Disarmed, searching for GPS.

Flashing Green Disarmed, GPS lock acquired. Ready to arm

Solid Blue Armed without GPS lock. Do not fly

Solid Green Armed with GPS lock. Ready to fly

Solid Red Failed to boot or read the microSD card

Flashing Yellow RC failsafe or battery failsafe activated

Flashing Yellow & Blue GPS glitch or GPS failsafe activated

5. Flight Surfaces - Check Movement

Directly after the battery is connected, move the right stick on the transmitter to test flight 

surface movement.

Caution: If the servos do not respond to manual inputs, the autopilot may attempt to apply 

throttle. If the throttle safety key is not inserted, the propeller may rotate, causing equipment 

damage and/or personnel injury. 

Preflight Part 2: GCS Checks

Section 2 involves configuring the autopilot. To the greatest extent possible, the checklist moves through the 

GCS menus top to bottom, left to right. This permits the use of “flows,” or logical, memorized progressions 

through the menus. Experienced operators use flows to perform short series of steps from memory and then 

consult the checklist to verify no steps were missed. 

GCS Power On

1. GCS Device - Power On

Turn on the GCS device (Windows laptop, tablet, etc.) Ensure that sufficient battery remains to 

complete the mission.

Note: While the GCS computer is necessary for pre-flight checks, the computer may be shut 

down during flight to conserve battery power. 
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2. Telemetry Radio - Attach

Ensure the 915 MHz antenna is securely attached to the ground telemetry radio. Connect a Micro 

USB cable to the ground telemetry radio and plug the cable into the GCS. 

Caution: Powering on the ground telemetry radio with no antenna attached may result in 

equipment damage and/or malfunction.

 

Left: Attach the antenna to the ground telemetry radio. Right: Connect the telemetry radio to your GCS device via 

USB

3. Mission Planner - Start

Flight Data Screen

4. Mission Planner - Connect

In the top right corner of Mission Planner, set the correct COM port for the ground telemetry 

radio, ensure the baud rate is set to 57600, and click Connect. The dialog box in the middle of the 

screen should display parameters as they are downloaded from the aircraft; the box will then 

disappear. 

If Mission Planner does not connect successfully look at the following table to asses telemetry 

radio status. The aircraft will not connect until the autopilot has booted to the flashing (or solid) 

blue or green states.

Note: All warnings on the HUD should clear in approximately 30 seconds after connecting. If not, 

wait until the aircraft has acquired GPS. Then power cycle the aircraft and reconnect.

Telemetry Radio LED Status

Blinking Green Searching for another radio

Solid Green Link has been established with another radio

Blinking Red Transmitting Data

Solid Red In firmware update Mode
AFM 2-4

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Initial Setup Screen

5. Compass - Enable, Check Declination, Calibrate if Needed

On the Initial Setup tab, expand the Mandatory Hardware tab on the left, and select the 

Compass tab. Ensure the Enable box is checked. If the Auto Declination box is checked, ensure 

that the declination is correct for your geographical region. If not, uncheck the Auto Dec box and 

manually set the compass declination.

6. New Field - Range Check/ Magnetometer Calibration

When operating at a field for the first time, it is recommended to perform a radio control range 

check to identify unknown sources of interference. On the handheld transmitter, press the menu 

button and scroll down to Range Check and press in on the scroll wheel. The radio screen will 

give instructions to press and hold the black trainer/stopwatch button to check the range. Walk 

30 meters away while maintaining line-of-sight with the aircraft. At this distance, control should 

be maintained. If control is lost, check for external sources of electromagnetic interference, such 

as nearby transmission equipment or power lines. Exit the range check by pressing the back 

button.

When operating in a new geographic location, it is important to perform a magnetometer 

calibration after appropriately setting the magnetic declination to ensure correct navigation. Go 

to the Initial Setup tab, expand the Mandatory Hardware tab on the left, and open the Compass 

menu. Click Live Calibration to begin the calibration process. Rotate the plane about all axes, and 

observe the on-screen display. The display portrays a sphere of points. The sphere should be 

completely and evenly covered with data points, with no large white data points remaining. It is 

recommended to collect at least 500 data points as indicated on the screen, or check the box 

labeled “Use Auto Accept.” Click Complete when done. Power cycle the aircraft, and then after 

reconnecting, observe the heading indications on the Flight Data Screen to ensure the indicated 

heading is correct. 

7. Flight Modes - Set

Open the Flight Modes tab on the left. Ensure that the flight modes are correctly set. Flight mode 

1 should be set to RTL, and modes 2 and 3 should be set to Auto, modes 4 and 5 should be set to 

loiter, and mode 6 to manual. If any changes are made, Press the Save Changes button.

Note: While RTL must be mode 1, and manual must be mode 6, the other modes may be 

changed to suit the intended flight.

8. Failsafe - Disabled

Open the Failsafe tab on the left. A warning will open advising to ensure that props are not 

connected; as long as the throttle safety key is installed this warning can safely be ignored. 

Ensure that all failsafe modes are disabled (all boxes unchecked). 

Note: The lost link failsafe is satisfied by flight mode 1 being set to RTL in the previous step. This 

is due to Lynx using an external pass-through for manual controls via a multiplexer.
AFM 2-4

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9. Airspeed - Enable and Use

Expand the Optional Hardware tab and select the Airspeed tab. Check the two boxes labeled 

“Airspeed Enable” and “Airspeed Use.”

10. Battery - Enable and Verify

Expand the Optional Hardware tab and select the Battery Monitor tab. The Monitor dropbox 

should be configured to measure just battery voltage, and the “APM Ver” dropbox should be set 

to Pixhawk. Verify battery voltage measured with the battery tester matches the value displayed 

on the Heads-Up Display (HUD). If it is not correct then enter the voltage indicated by the battery 

tester in the field labeled “Measured battery voltage”. 

Flight Planning Screen

11. Default Altitude - Set

Expand the green Waypoints bar at the bottom of the flight planning screen. Type the default 

altitude for the flight in the default altitude window. 

12. Loiter and Waypoint Radius - Set 30, 105

Type the desired loiter radius in the Loiter Radius window. The loiter radius is recommended to 

be 105 meters for a gentle turn. The waypoint radius should be 30 meters.

13. Takeoff - Create

Create an auto takeoff waypoint. If doing a manual takeoff, skip this step.

How To: Create an Auto Takeoff

Begin on the Flight Planner screen. Expand the green Waypoints bar at the bottom of the screen and the make 

sure that there is no previous mission or waypoints loaded. Previous waypoints may be deleted by right clicking on 

the map and selecting Clear Mission. A Takeoff waypoint can be added by right clicking on the map and select 

Takeoff from the menu. Enter the altitude as 60 meters and pitch angle as 15 degrees when prompted. 

Alternatively, in the Waypoints toolbar, click Add Below to add a new waypoint. From the drop down menu under 

the Command column select Takeoff. Set the value in the Pitch angle column to be 15 (degrees) and the value in 

the Alt column to be 60 (meters). The aircraft will hold the heading it was launched at, climb at the minimum pitch 

angle entered, and continue its climb until the takeoff altitude is achieved. Lynx will then proceed to the next 

waypoint.
AFM 2-4

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The Waypoints toolbar on the Flight Plan screen.

If no other waypoints are needed, a loiter waypoint should be added so that the aircraft proceeds to a desired 

location following the launch. To add the loiter point, right click on the map in the desired location, and selecting 

Loiter -> Forever from the menu. Alternatively click on the map where you would like to loiter, this will add 

another waypoint to the list in the Waypoints toolbar. Then from the Command drop down menu for the 

waypoint select LOITER_UNLIM. Finish by clicking Write WPs on the right of the screen.

14. Mission - Create/Load 

Create a mission and press Write WPs. Even if no flight plan is required, it is necessary to load a 

mission to fully test the autopilot’s functionality. Verify that all waypoints in the mission have a 

valid altitude.

Note: The autopilot can handle just over 700 waypoints. Additional waypoints will be rejected. 

The last waypoint in the mission will always be the last to upload.

Caution: Creating/loading a mission in the preflight overwrites any previous missions. Failure to 

create/load a mission in the preflight could cause the aircraft to navigate to the mission area of a 

prior flight, possibly causing an inadvertent fly-away and subsequent RTL. 

How To: Create a Mapping Mission

Beginning on the Flight Plan screen, zoom the map to the appropriate level so that the entire area of interest is 

visible. Right click on the map. Under the Draw Polygon option, click Add Polygon Point. Acknowledge the dialog 

box that comes up. Add polygon points to the map by left clicking in order to outline the desired area. Points can 

be dragged after they are placed, or removed by right clicking upon the map. Once the area has been fully 

outlined, right click on the map again and select Survey (Grid) from the Auto WP menu. This will open the Survey 

Grid menu.
AFM 2-4

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The Survey Grid menu.

In the Survey Grid menu, start with the Simple tab. If the camera parameters have previously been saved select 

the camera from the Camera dropbox. Enter the flight altitude in meters. Altering the Angle [deg] box changes the 

heading (and reciprocal) at which the aircraft will fly the grid pattern. Consider the wind direction, shape of your 

polygon, terrain, and LOS when choosing the angle. A crab angle is preferred over a headwind/tailwind scenario for 

even camera trigger timing. The checkbox labeled Camera top facing forward should be selected. Make sure to 

uncheck the Add Takeoff and Land WP’s box. Ensure the Advanced Options check box is enabled near the bottom 

of the Simple tab.

Moving to the Camera Config tab, check that the camera options are set appropriately. If this is the first time that 

the camera parameters have been provided they may be saved with the Save button for future use.

Camera Image Width 

(Pix)

Image Height 

(Pix)

Sensor Width 

(mm)

Sensor Height 

(mm)

Focal Length

Canon EOS M 5184 3456 22.3 14.9 22 mm

Sony NEX-7 6000 4000 23.5 15.6 20 mm

Sony a5100 6000 4000 23.5 15.6 20 mm 

Sony Alpha 7R 7360 4912 35.9 24 35 mm

Moving to the Grid Options tab, choose the Overlap [%] and Sidelap [%] numbers; at least 65% for both is 

recommend when using Agisoft Photoscan. The overlap and sidelap numbers are largely based on the 

requirements of your stitching software. 

Note the stats displayed at the bottom of the screen. There is a field called “Distance between images.” Take note 

of the value here in meters. This will later be needed for the camera trigger distance. Try to keep the trigger 

distance above 25 meters for proper camera timing (i.e. a small trigger distance may require the camera to take 

pictures faster than what it is capable of). 
AFM 2-4

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Note the distance between images in the Stats display.

The StartFrom dropbox controls the order in which the aircraft will proceed through the waypoints.

The OverShoot [m] fields (one for each side of the mission) control how far the aircraft will overshoot the polygon 

before turning. 45 meters of overshoot is recommended. Alternatively, the original polygon can be oversized for 

the same effect.

Move back to the Simple tab and select the Accept button to create the mission. 

Move to the Flight Plan screen and expand the green Waypoints bar. Delete the waypoint near the start of the 

mission and the end of the mission called DO_SET_CAM_TRIGG_DIST by clicking the X button. Click the Write WPs

button on the right side of the screen. 

Move to the Config/Tuning tab at the top of the screen. Select the Full Parameter Tree from the left menu. 

Expand the CAM entry. Select the value for CAM_TRIGG_DIST and enter the number for “distance between 

images” that was noted earlier. After entering the value select Write Params.

The Full Parameter Tree Menu.

Lynx will stop taking photos when the mission is complete. If the mission is restarted, or if a new mission is 

uploaded, the autopilot will resume sending trigger commands to the camera.
AFM 2-4

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15. Rally Points - Create/Load

Rally points are additional waypoints that the aircraft will divert to in case of RTL; the aircraft will 

fly to the nearest one. To clear any rally points that may already be created, right click on the 

map and scroll down to the Rally Points and select Clear Rally Points. To create rally points, right 

click on the map, scroll down to Rally Points, select Set Rally Point. Choose an altitude that will 

remain clear of surrounding terrain if the aircraft must navigate to the point. Add as many rally 

points as are needed to cover the mission area. Upload rally points by selecting Upload under the 

same menu; they are not automatically uploaded as part of the Write WPs button.

Note: The autopilot is capable of handling up to 50 rally points.

Caution: Creating/loading rally points will overwrite any previous rally points. Failure to 

create/load rally points in the preflight could cause the aircraft to navigate to the previous rally 

points or to home if the aircraft is in RTL or loses link. Always ensure that the rally points are 

known before any flight.

16. Waypoints - Read Back and Verify

Click the Read WPs button to read the waypoints back to the ground station. Mission Planner will 

ask if you want to clear your current mission, select yes. After all the waypoints have been 

downloaded make sure that all the waypoints displayed match the expected flight, and that the 

altitudes are correct. If prompted to reset the home to loaded coordinates select yes.

Caution: Failure to read back waypoints could result in not detecting a corrupted mission, which 

could result in the aircraft navigating to unexpected locations, possibly resulting in a loss of the 

system and cause injury.

Flight Data Screen

17. Camera Synchronization - Perform

Under the HUD select the tab labeled “Scripts,” press the Select Script button to select the 

tagging script that was provided with SwiftTag “triggerSync.py.” Power on the camera and verify 

desired settings. Walk with the fuselage until a picture is taken, this should be roughly the 

distance that has been entered as CAM_TRIG_DIST. After a picture is taken, stop walking with the 

fuselage and select Run Script. A dialog box will open saying “Syncing log...” - close the box once 

the script says “Complete!” Repeat the walk test with an object in the camera’s field of view that 

you will be able to recognize later, when tagging with SwiftTag.

Camera Settings Value

Shooting Mode Shutter Priority

ISO Speed (Sensor Sensitivity) Auto

Aperture (Depth of Field) Auto

Shutter Speed (Exposure) 1/2500 second. 

White Balance Daytime, Cloudy, or Auto. Select the appropriate white balance based on 

current lighting conditions.
AFM 2-4

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Dynamic Range Optimization (DRO) Low Level or Off. The DRO function analyzes the contrast and produces 

an image with optimal brightness and recovered shadow detail. Useful 

in low light situations where long shadows may obscure details.

High Dynamic Range (HDR) Off

Focus Mode Single-shot AF

Focus Area Wide

LCD Screen Brightness As low as possible. Reducing LCD brightness will increase camera battery 

life. This is essential for long photomapping flights.

Auto Exposure Lock (AEL) On

Preflight Part 3: System Checks

The final section of the preflight involves physical checks of the aircraft systems. These checks involve two 

crewmembers: the Aircraft Operator on the GCS and the Safety Pilot holding or moving the aircraft. With 

experience, these steps can be performed from memory, but always consult the checklist afterward to ensure 

that no steps were missed.

1. Autopilot Arm - Verify

Verify that the HUD is not showing DISARMED if it is, select the Arm/Disarm button under the 

actions tab to arm the autopilot.

2. HUD - Verify Level and Responsive

Verify that the HUD is showing the current orientation of the aircraft. Tilt the aircraft to verify 

that the HUD is responsive, indicating that link is established. 

3. Magnetometer - Correct and Responsive

Point the fuselage in a known direction and verify that the map agrees. If off by more than 5 

degrees a compass calibration is needed before flight operations. Having verified the compass 

points in the correct direction, turn the fuselage in a series of 90 degree turns while watching the 

heading on the HUD. The AO is watching to make sure that the indicated heading is correct and 

matches the direction of the turns, and that no “Bad Compass Health” warnings appear. If this 

fails verify compass orientation, declination and calibration. 

Caution: Failure to verify the correct response and heading of the compass can lead to erratic 

and unpredictable behavior in flight.

4. Flight Surface Checks - Perform

Using the transmitter, move the flight surfaces to their limits. Announce the control surface 

being moved and the direction being commanded, “Pitch Up, Pitch Down, Roll Right, Roll Left.” 

Both AO and SP should watch the flight surfaces and confirm correct movement. Engage the 

deep-stall switch and ensure that the stabilator deflects up. Disengage the deep-stall switch.
AFM 2-4

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5. Mode Select - Verify

Move the mode switch on the transmitter through each position and verify the autopilot enters 

the expected mode. When not in manual, the surfaces should move from the autopilot control.

Note: Ensure the throttle safety key is installed before transferring control to the autopilot.

6. AP Pass-Through Check - Perform

Deflect the mode switch on the transmitter to one of the autopilot modes. On the Flight Data 

screen under the Actions tab, select Manual from the third dropbox. Press Set Mode. Using the 

transmitter, repeat flight surface checks for pitch and roll.

7. IMU Test - Perform

Under the Actions tab, select Stabilize from the third dropbox. Press Set Mode. Hold the fuselage 

and test the flight surfaces’ response to rotations in all three axes: pitch, roll, and yaw. The flight 

surfaces should oppose the movement in each direction. For example, when the plane is pointed 

down, the stabilator should command the plane to pitch up. The rudder should oppose both roll 

and yaw movements. After completing the check move the mode switch back to manual.

8. Auto Check - Perform

Under the Actions tab, select the Auto button then select Restart Mission. In the lower right 

corner of the HUD, verify the autopilot mode displays Auto. If using an auto takeoff, verify that 

the aircraft commands 100% throttle out by observing the HUD. Select the second dropbox from 

the actions tab and select the number 2, press the Set WP button to make this the current 

waypoint. Directly below Auto on the HUD, you will see #># (for example 200>2). This is the 

“distance to current WP” and is saying that waypoint 2 is 200 meters away. Next, verify that the 

yellow line on the map is pointed towards waypoint 2. Finish by selecting Manual from the third 

dropbox, and then press Set Mode followed by Restart Mission.

9. Return To Launch (RTL) - Perform

With throttle safety key still attached, turn off the transmitter and confirm that the autopilot 

mode changes to RTL. If rally points are used, both the “distance to current WP” and the yellow 

line should correspond to the nearest point. If no rally points are uploaded, the distance should 

be from the home location with the yellow line pointing at home. Turn the transmitter back on.

Caution: If the RTL distance is unexpectedly large and/or the aircraft does not appear to be 

navigating (yellow line) to the correct RTL point, do not proceed without first correcting the rally 

points or home location. Failure to do so can cause a flyaway if RTL is entered.

10. GPS - Verify at Least 6 Satellites

Verify that the HUD states “GPS: 3D Fix” and that the number of satellites is at least 6. The 

number of satellites is displayed at the bottom of the map on the Flight Data tab.

Caution: Extended Kalman Filters (EKF) will not initialize without at least 6 satellites, and the GPS 

will be unreliable without at least 6 satellites.
AFM 2-4

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11. Preflight Calibration - Perform

Under the Actions tab, select PREFLIGHT CALIBRATION from the first drobox. While shielding the 

pitot tube from any wind, press the Do Action button beside the dropbox. Wait until the altitude 

and airspeed zeroize. 

Note: If launch becomes delayed, it may be necessary to perform another preflight calibration 

before takeoff. Changes in weather will cause the altitude and airspeed to drift. It is typical for 

airspeed to not fully zeroize on the ground. Airspeed readings around 2m/s are acceptable. 

Caution: Do not perform a preflight calibration in flight. Doing so will cause the aircraft to climb 

and increase speed, possibly resulting in damage/loss. 

12. Airspeed Test - Perform

To ensure the airspeed sensor is functioning, blow over the pitot tube and observe the airspeed 

increasing on the GCS screen. Speeds greater than 12 m/s should be observed. 

13. GCS HUD - No Errors/Warnings

Check that the HUD on the GCS is not indicating any warnings. All warnings or errors must be 

cleared before flight.

14. Stabilator - Attach

With the labeled side facing upward, line up the stabilator arm and slide the stabilator onto the 

end of the fuselage until it clips into place.

 

Left: Clip the stabilator onto the fuselage with the appropriate side facing up. Right: Insert the wishbones into the 

wing’s spars 

15. Wing - Assemble and Attach

Insert the wishbones into the center wing spars, angled up. Attach the outboard wings to the 

center wing by sliding the wishbones into the outboard wing spars. Ensure the wings’ leading and 

trailing edges are aligned by adjusting the wishbones. Apply a small strip of gaffer’s tape near the 

leading edge between the center and outboard wings. Place the wings on top of the fuselage. 

Align the label on the center wing to the fuselage and slide the wings to the rear until they are 

fully seated.

Note: The friction between the center wing and the fuselage can be adjusted with the wing bolts.
AFM 2-4

26

 

Left: Attach the outboard wings to the center wing by aligning the wishbones. Slide the wings together until the ribs 

touch. Ensure the trailing edge lines up between the outboard and center wing. Right: Place the center wing on the 

fuselage and slide it back until it locks in place. The label on the center wing and fuselage should align.

 

16. Full Throttle Check - Perform

Hold the aircraft firmly and pointed in a safe direction and into the wind. Remove the throttle 

safety key. Listen for the motor arming tone visually check for the red light near the safety key. 

Using the transmitter, smoothly advance the throttle to full. Hold full throttle for one to two 

seconds, then reduce throttle to off. Replace the throttle key; the red light should turn off.

Warning: Rotating propellers can cause serious injury or death. Keep body parts clear of the 

propeller arc. Stay out of danger zones which include directly in front of the aircraft, and to the 

right and left of the propeller. 

Caution: If excessive vibration is felt or excessive noise is heard during the full throttle check, 

reduce the throttle IMMEDIATELY and check for the cause. Excessive vibration can be destructive 

to the airframe and power components. Ensure that all motor and spinner hardware is tightened, 

that propellers are in good condition, that the motor is spinning clockwise (when viewed from 

behind), and the aircraft is facing into the wind. Performing the full throttle check with a tailwind 

will cause the propeller to stall, resulting in noise and excessive vibration. 

Takeoff

The takeoff checklist is a final verification of critical systems and a systematic procedure for safely launching 

the aircraft. 

1. Payload - Ready for Takeoff 

Determine that the camera is on and configured correctly. Ensure the lens is clean.

2. Wind - Check

Confirm that wind is within limitations and observe the wind direction. 

3. Launch Direction - Into wind
AFM 2-4

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4. Launch Area - Clear

Visually determine that the desired launch area is appropriate and safe for the takeoff, and that 

the area is clear of any bystanders and obstacles.

5. Mode Manual - Verify (SP)

Ensure that the handheld transmitter is set to manual.

Manual Takeoff

6. Propeller - Clear (Thrower)

Ensure that the propeller blades are extended and clear of the fuselage and skid pads.

7. Throttle Safety Key - Remove (Thrower)

8. Ready For Takeoff - Announce (SP)

9. Ready For Takeoff - Confirm (Thrower)

This is a challenge-response between the Safety Pilot and the crewmember throwing. No other 

phraseology should be used so that no miscommunication can occur. 

10. Timer - Start (SP)

11. Full Throttle - Set (SP)

12. Full Throttle - Verify (Thrower)

The thrower will wait until the aircraft is at full throttle. 

13. Aircraft - Launch Into Wind (Thrower)

Grasp Lynx at the bottom of the tail and support the front of the fuselage with the other hand. 

With the aircraft pointed horizontal, throw with the rear hand like a javelin. Concentrate on 

throwing the aircraft straight and level.

Note: If the aircraft is inadvertently thrown into an unusual attitude or stall, the Safety Pilot must 

quickly make a go/no-go decision. The Safety Pilot must either attempt to recover from the 

unusual attitude and climb out, or reduce power and land. Experience will dictate which course 

of action is more favorable. 

Left: Grasp Lynx at the bottom of the tail with your dominant hand and support the front of the fuselage with your 

other hand. Raise the aircraft above your head to clear the stabilator. Right: Throw Lynx with your dominant hand. 

Focus on throwing straight and level as shown.
AFM 2-4

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Auto Takeoff

6. Mission - Restart and Verify (AO)

On the Flight Data screen under the Actions tab, select Restart Mission. 

7. Propeller - Clear (Thrower)

Ensure that the propeller blades are extended and clear of the fuselage and skid pads.

8. Throttle Safety Key - Remove (Thrower)

9. Ready For Takeoff - Announce (SP)

10. Ready For Takeoff - Confirm (Thrower)

This is a challenge-response between the Safety Pilot and the crewmember throwing. No other 

phraseology should be used so that no miscommunication can occur. 

11. Timer - Start (SP)

12. Mode - Auto (SP)

Deflect the mode switch on the handheld transmitter to auto. The aircraft will now be under 

autopilot control and in mode auto. Full throttle will be applied almost immediately after 

entering auto.

Caution: The heading of the aircraft when entering auto will be used as the takeoff heading. If 

the aircraft is not facing the right direction for takeoff, or if the control is ever transitioned out of 

auto, the takeoff procedure should be restarted.

13. Half Throttle - Set (SP)

The safety pilot will set the throttle on the transmitter to approximately 50%. This will allow for a 

smoother recovery if manual control needs to be taken during the auto takeoff.

14. Full Throttle - Verify (Thrower)

The thrower will wait until the aircraft is at full throttle. 

Caution: If full throttle is not applied, the aircraft may be in the wrong mode or incorrectly set up. 

Proceeding with the launch could lead to a crash.

15. Aircraft - Launch Into Wind (Thrower)

Grasp Lynx at the bottom of the tail and support the front of the fuselage with the other hand. 

With the aircraft pointed horizontal, throw with the rear hand like a javelin. Concentrate on 

throwing the aircraft straight and level.

Landing

Lynx should be landed when battery voltage has dropped to 3.3 volts per cell.

Caution: The ESC will momentarily cut power to the motor whenever cell voltage drops below 3.0 

to protect the battery. Use of full throttle at voltages lower than 3.3 volts per cell, such as in a goaround or wave-off, may result in a temporary loss of power due to voltage sag triggering the ESC 

cutoff.
AFM 2-4

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1. Weather/Winds - Verify (AO)

Check the wind direction and speed.

2. Recovery Site - Select (SP)

Choose a suitable site for recovery. If utilizing a deep-stall, only a small space is needed (~30 

meters). Select a site to minimize potential airframe damage. The angle at which the aircraft

descends is dependent on the wind. A strong headwind will result in a steeper deep-stalls and 

belly lands. No headwind will result in about a 45 degree deep-stall descent. 

If a belly landing is to be used, utilize a large (at least 90 meter long) field, free of obstacles on 

the approach side. The approach angle of the plane will be very shallow (~3 degrees). 

Note: For either landing method, experience will dictate how much space is ultimately required. 

Obstacles and wind are major factors in determining required space. 

3. Recovery Site Clear - Verify (Observer)

Ensure that the recovery site and the approach path are clear of obstacles and personnel. 

Deep-Stall Landing

4. Altitude - Greater than 30 meters Above Ground Level (AGL) (SP)

Engage the deep-stall at 30 meters AGL or higher. This will ensure Lynx has enough time to settle 

into a stable descent. It also gives the Safety Pilot room to abort the deep-stall if necessary. 

5. Heading - Into Wind (SP/AO)

6. Throttle - Off (SP)

Just before engaging deep-stall, reduce throttle to zero.

Note: Throttle is programmed to automatically turn off during deep-stall, however, it is prudent 

to also manually reduce the throttle. 

7. Deep Stall - Engage (SP)

8. Heading Into Wind - Maintain (SP)

Ensure the aircraft’s heading remains into the wind by steering with large deflections of the 

rudder. Typically the aircraft will weathervane into the wind and little input is needed. The 

aircraft’s pitch is locked during deep-stall.

9. Timer- Stop (SP)

Tip: Deep-Stall Approach

Either the Safety Pilot can manually fly the deep-stall approach, or the AO can create a simple flight plan that flies 

the approach (i.e., into the wind). Remember, this is not a landing waypoint in Mission Planner because the deepstall is engaged from the mission altitude.

Alternatively, the AO can have the aircraft loiter over the landing site. When the aircraft points into the wind, 

simply engage the deep-stall and maintain a headwind during the descent.
AFM 2-4

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Tip: Deep-Stall Suitability

Lynx is an extremely rugged aircraft designed to handle repeated deep-stall impacts. However, deep-stall landings

will reduce the life of the airframe. Deep-stalling does have its advantages over belly landing: it is easier, faster, 

steeper, and more predictable. The potential for pilot error is also reduced because the pilot only controls heading.

Belly landing should be reserved for experienced users.

The area selected for a deep-stall should seek to minimize risk to the airframe. The graphic below attempts to 

show the suitability of terrain.

Belly Landing

4. Manually Land - Into Wind (SP)

To perform a manual landing, navigate the aircraft to about 300 meters away downwind from 

the landing area, reduce throttle to zero, and circle to descend. When the aircraft reaches about 

45 meters AGL, turn towards the landing area. Hold the pitch level, and allow the aircraft to 

descend. If you overshoot the desired landing area, either continue the landing descent (if 

obstacles permit), or climb to a safe altitude and reattempt the landing.

Caution: Landings that result in Lynx resting out of sight of the Safety Pilot may cause the aircraft 

to enter RTL due to ground interfere with the 2.4 GHz manual control link.

Caution: Maneuvering just above stall speed is the most common mistake associated with belly 

landings. When the aircraft experiences a high load, such as turning onto final approach, the stall 

speed is increased. Always fly with a safe margin of airspeed.

5. Timer- Stop (SP)
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Post Flight

1. Flight Battery - Disconnect/Check

Using the handheld battery tester, check the voltage of the battery. Pack voltage should be at 

least 19.8 volts. Check each individual cell by pressing the cell button. Each cell should be greater 

than 3.3 volts. If an individual cell shows greater than 0.1 volt difference from the rest, there may 

be a problem with that cell. Monitor the battery closely post-flight and feel for any heat that 

continues to originate from the battery (the pack will be warm after normal use). 

Warning: LiPo batteries are flammable and can ignite without external sources of ignition. If the 

Lithium battery feels hot post-flight, place the battery in a safe location away from flammables. 

Note: Discharging a LiPo battery below 3.0 volts per cell may cause permanent battery capacity 

loss and physical deformation (swollen, puffy, etc.)

Note: Storing LiPo batteries at high capacity or in high temperatures for long durations can result 

in permanent battery capacity loss and physical deformation (swollen, puffy, etc.). Store 

batteries at half capacity or approximately 3.7v per cell. 

2. Handheld Transmitter – Off (SP)

When the flight battery is disconnected, the transmitter may be powered off. Note the flight 

time if needed for logging purposes.

3. Aircraft - Disassemble/Inspect 

While disassembling, be sure to inspect all parts, looking for damage. Carefully remove any 

gaffer’s tape from the wings; pull the tape from the leading edge back. Remove the outboard 

wings from the center wing. Ensure that all four wishbones are accounted for and place them in 

the spares kit. Unless already detached, remove the center wing by placing your hand atop the 

surface (palm down, fingers spread); apply light pressure and slide it forward. Remove the 

stabilator by pulling it to the rear. Deflect the stabilator arm upward for transport. Detach the 

pitot tube from its clip, leaving it hanging by the flexible tubing. Stow all components for 

transport. 

4. GCS – Shutdown (AO)

Close Mission Planner and shutdown the GCS.

Photo Tagging

The autopilot has removable micro SD card that stores flight logs. The flight log is needed to geo-tag photos.

Start by removing the camera from the payload bay. Next remove the foam camera block. With this removed, the 

autopilot’s micro SD card is accessible. Remove the micro SD Card from the autopilot. 
AFM 2-4

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Payload bay with camera removed.

Insert the micro SD Card into your GCS device. Open Mission Planner. On the Flight Data tab, below the HUD,

there is a row of tabs. Select the DataFlash Logs tab and then select the “PX4 .Bin to .Log” button. It will ask you to 

select the autopilot log; this will be in the APM/LOGS folder on the micro SD card. 
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The DataFlash Logs menu in Mission Planner

Typically the last flight will be the most recent file (and the largest number in the filename). It will then ask you 

where to save the .log. As long as you do not save the .log on the autopilot’s SD card, it does not matter where it is 

saved. Normally you would save the .log where the images will also be stored.

After Mission Planner has completed the conversion of the log you can remove the micro SD card and reinstall it in 

the autopilot. Next, copy the photos from camera. Open SwiftTag and click the Choose Autopilot Log button and 

select the .log file you generated earlier. Then select the Choose Photo Folder button and select the folder that 

contains your images. Looking through the images, identify the sync photo. Moving back to SwiftTag, click the 

Select Sync Photo button and choose the photo you just identified. The Tagging Options button will bring up a 

menu for filtering and omitting photos based on aircraft attitude. Alternatively, filtering photos by attitude can 

effectively be done in image processing software. Finish by selecting Tag Photos.
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SwiftTag

SwiftTag will attempt to read the timestamps for all photos and find the synchronization mark within the log. You 

will then be asked where to save the tagged camera positions; typically this can be the same folder as your photos. 

The file will be a CSV file, readable by most image processing programs.

Battery Charging

The battery charger has been pre-set with the appropriate settings in Memory 1 as per the following table.

Setting Value

BATT TYPE LiPo

BATT VOLTS 22.2v pack ( 6S)

BATT CAPACITY 11000mAH

CHARGE CURRENT 11.0 A

TEMPERATURE CUT-OFF 50C

SAFETY TIMER 120 min

TCS CAPACITY 100%

TCS END ACTION Continue

TVC = YOUR RISK +0mV 4.200Vc/C

DISCHARGE AMPS 5.0 A

DISCHARGE VOLTS 3.8 V/Cell

SET STORAGE TCS 60%

First connect the charging cable and balance board to the charger. Next, connect the charger to the power supply. 

Left: Charging cable. Right: Balance board connected.
AFM 2-4

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Left: Power supply lead connected. Right: Connect the charger and power supply.

Plug in the power supply to a wall outlet (110 - 220 Vac).

Connect the battery lead (blue connector) to the charger followed by the balance plug.

Battery pack connected to the charger.

Verify the battery charging settings. Then, with the battery connected, start the process by holding down the enter 

button. This will bring up a screen that prompts if you want to do a SOLO CHARGE, press and hold enter again until 

it reads Checking Battery. It will then show the current battery pack voltage and say that it has detected 6 cells. 

Press enter to start charging. Note, if the charger does not say 6 cells, do not proceed. Press mode to cancel the 

charge and verify all settings are correct and that the battery is not damaged.

When the battery is full, the charger will play a short musical tone and the LCD display will flash “END.” Press and 

hold enter to end the charge cycle and return to the main menu. The battery can now be disconnected.
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Section 5: Emergency Procedures

The following section details the likely best course of action to take in the event of some emergencies. Not all 

emergencies can be planned for, and the situation will always dictate the best course of action. You, as the 

operator, must think quickly during an emergency to make the right decision(s). Your first priority in an emergency 

is to protect human life- both that of your crew, and that of the public. Your second priority is to minimize damage 

to equipment and property.

In the following emergency procedures, the lines that are underlined are “immediate action items,” and should be 

performed from memory. In any emergency situation, while one operator is performing the immediate action 

items, the other operator should turn to the appropriate page in the checklist. Using the checklist, confirm that the 

immediate action items were performed correctly, and see if there are any additional steps. 

Motor Failure Below 30 meters AGL

1. Control - Manual (SP)

Deflect the autopilot switch on the transmitter to manual and take control of the aircraft. The 

flight surfaces should be operational, but no throttle will be available. 

2. Safe Heading - Establish (SP)

Descent to a desired landing spot will not be possible, so attempt to point the aircraft in a safe 

direction. 

3. Deep-Stall - Engage (SP)

Engage the deep-stall switch. 

Note: All crewmembers should assist in securing the aircraft. If there are bystanders, attempt to 

keep them away from the aircraft. Insert the throttle safety key as soon as possible. If possible, 

disconnect the flight battery.

Warning: If a LiPo battery is punctured or ruptured, use extreme caution in handling. Exposed 

Lithium may catch fire without external sources of ignition. Keep away from flammable 

materials. 

Motor Failure Above 30 meters AGL

1. Control - Manual (SP)

Deflect the mode switch on the transmitter to manual, and take control of the aircraft. The flight 

surfaces should be operational, but no throttle will be available. 

2. Throttle - Reduce (SP)

Immediately reduce the throttle to off. If the battery is temporarily depleted because of voltage 

sag, it may regain a small amount of voltage while gliding. As a result, there may be a small 

amount of power available during the final approach. 
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3. Safe Heading - Establish (SP)

Point the aircraft in a safe direction, away from persons or property and viable for landing. 

4. Recovery Site - Select (Observer)

Determine the optimal landing spot.

5. Land or Deep-Stall - ASAP (SP)

Perform a deep-stall or belly land as soon as possible. 

Uncontrolled Flight

1. Control - Manual (SP)

Deflect the transmitter autopilot switch to Manual

2. Controllability - Assess (SP)

Quickly determine if the aircraft responds to Safety Pilot controls. 

If uncontrollable:

1. Deep-Stall - Engage (SP)

Remove the safety cover, if installed, and engage the deep-stall. 

2. Batteries - Secure 

Carefully check the battery for any punctures or ruptures. If any are found, the battery needs to 

be safely disposed of in accordance with local regulations.

If controllable:

1. Land – As soon as practical (SP)

Safety Pilot Low Battery

The transmitter will signal its battery is low by emitting a beeping noise and giving an on-screen warning that 

the battery is low. This is a critical emergency, and the aircraft must be recovered as soon as possible. Avoid 

this by either charging the transmitter fully before the flight, connecting the charger in-flight, or purchasing a 

lithium battery from Spektrum. 

1. Control - Manual (SP)

Deflect the autopilot switch on the transmitter to manual

2. Safe Heading - Establish (SP)

Point the aircraft in a safe direction, away from persons or property and viable for landing. 

3. Land or Deep-Stall - Immediately (SP)

Perform a deep-stall or belly land immediately. 
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Safety Pilot Uplink Failure

If the Safety Pilot loses the ability to control the aircraft, the aircraft will Return to Launch (RTL) and orbit at 

the default altitude. As the aircraft comes closer, attempt to regain manual control. If control cannot be 

regained, the Aircraft Operator must create and execute an autonomous landing flight plan. 

1. RTL - Verify (A0)

Upon loss of Safety Pilot uplink, the aircraft should enter RTL. Verify that the aircraft is 

proceeding to the RTL point at the default altitude. 

2. Control - Auto (SP)

The Safety Pilot should place the autopilot mode switch on the transmitter to auto if not already 

in auto. This will ensure that the aircraft completely returns to the launch point, which will aid in 

regaining control of the aircraft. 

3. Uplink - Re-Establish (SP)

Re-establish control with the transmitter. Control may be regained automatically when the 

aircraft comes within radio range. If control cannot be established, cycle the power on the 

transmitter. 

4. Autoland - As Appropriate (AO)

Create a flight plan on the GCS that commands the aircraft to land. The second to last waypoint 

should be 300 meters away, at 45 meters of altitude, and downwind. The final waypoint of the 

flight plan should be a LAND waypoint (selectable in the flight plan list), and the altitude for that 

point must be 0.

GPS Failure

If the GPS fails, the aircraft will continue to try to navigate using “dead reckoning.” This is an estimation of 

position based on angular velocities and lateral accelerations. Dead reckoning is highly inaccurate and will 

become exponentially erroneous over time. Do not rely on it to continue the mission or to navigate home. 

1. GPS Failure – Announce (A0)

When GPS failure is recognized, announce to all crewmembers. GPS failure will be signaled by a 

red warning on the HUD saying “Bad GPS Health.” If GCS audible alerts are configured, it will 

announce “Warning: Bad GPS Health.” 

2. Control - Manual (SP)

Deflect the transmitter autopilot switch to manual. 

3. Land - As Soon as Practical (SP)

Once manual control is gained, the aircraft is no longer in danger. 

GCS Low Battery

This procedure details what to do if the GCS laptop battery is too low to finish the mission. 

1. Screen Brightness – Reduce (AO)

If the laptop is still running, reduce the screen brightness to conserve battery power. 
AFM 2-4

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2. Power Source - Connect (AO)

Connect the GCS to an external power source to begin charging (if available). Sources of power 

while in the field can include USB battery packs, vehicle DC inverters and generators.

3. Land - As Soon as Practical (SP)

GCS Telemetry Fail

Temporary loss of GCS telemetry is normal when operating near the extent of the telemetry radio range. 

Range can be improved by adding a higher gain antenna to the ground radio. The aircraft will continue its 

flight plan without telemetry, but it is good practice to monitor its position and status as much as possible. 

1. Distance from Aircraft - Check (AO)

Check distance from GCS. If the distance is >850 meters out, it is probable that the loss is due 

simply to range. Link should resume automatically once closer.

2. Comms - Restart (AO)

If the aircraft is near the GCS and telemetry has not resumed, close Mission Planner. Then 

disconnect and reconnect the telemetry radio. Restart Mission Planner and connect. After 

connecting make sure to click the Read WPs button from the Flight Plan screen.

If telemetry cannot be restored:

3. Land – As Soon as Practical (SP)
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Illustrated: GCS Telemetry Failure Flowchart

Deep-Stall Abort

Much like a wave-off for a belly landing, a deep-stall may need to be aborted if the landing spot is not going to 

be hit. Aborting a deep-stall is not recommended below 30 meters AGL as disengaging the deep-stall will 
AFM 2-4

41

cause the aircraft to pitch down suddenly. A deep-stall can also be aborted if the safety pilot needs to descend 

rapidly but does not necessarily need to land; this procedure should be reserved for experienced pilots.

1. Deep-Stall - Disengage (SP)

Disengage the deep-stall switch to abort the deep-stall descent. 

2. Aircraft - Climb (SP)

3. Power - Apply (SP)

Increase throttle as needed once the aircraft is level.
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Section 6: Repair Instructions

This section describes the procedures for operator level repairs of the Lynx.

 Replacement of a propeller

 Replacement of a broken wing bolt

 Replacement of a tail clip

 Replacement of a stabilator arm

 Replacement of the motor

 Replacement of a servo

 Replacement of a skid pad

 Repairing wing delamination

 Re-Binding the DX7s Transmitter

In addition, a reference table for replacement hardware is listed.

Aside from normal inspections before and after flight, Lynx does not require any regular scheduled maintenance. 

List of Common Replacement Hardware

Item Hardware Specs

Wing Bolt Nylon 1/4" -20 x 1” hex cap screw or,

Fiberglass 1/4" -20 x 1” hex cap screw Motor Bulkhead Screw Nylon 6-32 x 3/8” Philips pan head screw

Servo Retaining Screw Nylon 6-32 x 3/8” Philips pan head screw

Throttle Key Retaining Screw Nylon 6-32 x 3/8” slotted flat head screw

Tail Clip Screw Steel 4-40 x 1/2” Philips pan head screw

Servo Linkage Screw Steel 4-40 x 1/2” Philips pan head screw

Servo Linkage Retaining Nut Steel 4-40 nylon-insert hex locknut
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Replacing a Propeller

If the propeller is broken, cracked, or chipped, it must be replaced. If you are unsure of the condition of a 

propeller, perform a quick throttle check. A damaged propeller can cause harmful vibrations to the airframe and 

will make a buffeting sound during the full throttle check.

It is possible that one propeller blade will break, and the other will remain intact. Replace only the broken side. 

Make certain that the two propeller blades are identical. Raised lettering near the center of the propeller indicates 

the diameter and pitch (i.e. 15 x 10).

To replace a propeller blade, use the crescent wrench and flathead screwdriver to remove the nut and screw

attached to the propeller yoke. Place the new propeller blade root into the yoke, ensuring that the printed 

lettering on the propeller is facing forward. Insert the screw and thread the lock nut into place and retighten. 

Tighten until the propeller has enough friction to remain in place when extended.

Remove a propeller using the crescent wrench and flathead screwdriver.

Replacing a Broken Wing Bolt

It is possible for one or more wing bolts to break upon landing. This is normal and prevents damage to the fuselage 

and wings. To replace a broken bolt, attempt to use pliers to twist off the broken shaft. If the bolt is completely 

recessed, insert the tip of an X-Acto blade into the plastic bolt and twist counter-clockwise to remove. It may be 

necessary to tap the backside of the knife to bury it deeper into the bolt. 
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An X-Acto blade removes a broken wing bolt.

If the bolt remains difficult to remove, drill a small hole into the center of the broken shaft and tap an X-Acto blade 

into the hole. The drilled hole will provide extra leverage for the blade.

Left: Broken wing bolt removed. The bolt will typically shear at the base of the hex cap. Right: Wing bolt spacer.

Insert the new wing bolt and turn clockwise. Use the wing bolt spacer and socket (if difficult to hand turn). Tighten 

down the new wing bolt until it touches the spacer. The spacer should leave roughly the correct gap for the center 

wing to slide on.

Replacing a Tail Clip

If any tail clips become cracked or broken, they must be replaced. To remove the broken tail clip, use the Phillips 

screwdriver to remove the screw inside the clip. Insert the screw into the replacement tail clip and reinstall with 

the Philips screwdriver. 
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Left: A cracked tail clip with screw removed. Right: Two clips ready to be installed.

A spare tail clip is installed with a Philips screwdriver.

Replacing a Stabilator Arm

If the carbon stabilator arm becomes cracked or broken, it must be replaced. Use the Phillips screwdriver and 

crescent wrench to remove the servo control rod from the stabilator arm. Ensure the control rod does not spin. 

Spinning the control rod will change the aircraft’s pitch trim. Use the Phillips screwdriver to remove the pivot 

spacer from the tail. With the spacer removed, the stabilator arm will come free. Insert the new stabilator arm into 

its slot, lining up the hole on the pivot point. Reinstall the pivot spacer and tighten just until resistance is felt.

Reattach the control rod to the stabilator arm.
AFM 2-4

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Left: Remove the control rod from the stabilator arm using the crescent wrench and Philips screwdriver. Note the 

offset nut on the right and the lock nut on the left. Right: Remove the pivot spacer with a Philips screwdriver. 

Pivot spacers and stabilator arm removed.

Replacing the Motor

If the motor does not spin freely, has a bent shaft, or makes a loud whining noise, it must be replaced.

First open the battery bay and remove the battery. Disconnect the three ESC wires connected to the motor. 

Remove the four metal counter-sunk screws holding the motor in place using a Philips screwdriver. Slide the motor 

forward and out.
AFM 2-4

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Left: Looking into the battery bay. The ESC and motor connect with three wires. Right: Four counter-sunk screws 

fasten the motor to the bulkhead.

 

Left: With the screws removed, the motor will slide out the front. Right: The bulkhead attaches to the motor mount 

with four nylon screws.

Remove the plastic spinner with a screwdriver. Remove the propeller nut using the crescent wrench. With the nut 

removed, grasp the motor and twist the hub off. Never attempt to pry the hub off by leveraging a screwdriver 

between the fuselage and propeller hub.

Left: plastic spinner removed. Right: Motor removed with propeller hub still attached.

Insert the replacement motor in from the nose, ensuring that the three motor wires are facing down and along the 

trough of the motor mount. The wires should enter the battery compartment. Attach the motor to the bulkhead 

with the four metal counter-sunk screws. 

Connect the motor and ESC wires.
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Slide the propeller hub onto the motor shaft. Leave an appropriate gap to ensure the hub spins freely without 

rubbing the fuselage. Tighten the propeller nut using the crescent wrench. A loose prop nut will cause the 

propeller to launch forward when full throttle is applied. Reattach the spinner.

Left: Spinner and propeller hub disassembled. Right: The prop nut fastens the hub to the motor. 

Power the transmitter and aircraft. Remove the throttle key and test the throttle. Ensure no rubbing occurs 

between the propeller hub and the fuselage. Ensure the propeller spins clockwise when viewed from behind.

Swapping any two motor/ESC wires will reverse the direction of the motor.

Replacing a Servo

If a servo is immobile, has stripped or partially stripped gears, makes a clicking noise, or cannot hold its position

properly, it must be replaced. The same procedure is used for either servo.

First remove the payload. Locate the multiplexer atop the Pixhawk autopilot. Identify the correct servo wire 

labeled either “R” (Rudder) or “E” (Elevator). Disconnect the wire from the multiplexer. Attach a string or wire to 

the end of the servo connector. The string should be approximately a meter in length and will serve as a wire guide 

when installing the replacement servo.

Disconnect the control rod using a Philips screwdriver and crescent wrench. Do not twist the control rod as this will 

affect the aircraft’s trim. Next, remove the two nylon screws holding the servo in place. Grasp the servo arm and 

slide the servo out from its tray. 

Left: Remove the two nylon retaining screws. Right: Servo removed from its tray.

Pull the servo and its wire out of the tail just until the string appears. Disconnect the servo connector from the 

string. 
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Ensure the arm on the replacement servo is mounted as close to possible as the original servo. (i.e. the new servo 

arm should physically stop in the same location as the servo being replace). Mounting the servo arm differently 

will affect aircraft trim and servo travel.

Attach the replacement servo connector to the string. Pull the string from the payload bay until the connector 

appears in the autopilot bay. Slide the servo into its tray and fasten with the two nylon screws. Reattach the 

control arm.

Connect the servo wire in the same place as the original servo, ensuring that connector’s orientation matches 

adjacent wires.

Power the transmitter and aircraft. Test the control surface. Additional trim or sub trim may need to be added to 

match the original neutral control surface position. If trim is added, perform a radio calibration in Mission Planner.

A manual flight may be necessary if you are unsure of the trim values on the ground.

Replacing a Skid Pad

Normal wear (cuts, abrasion, dents) of the skid pads can be patched with gaffer’s tape.

If a skid pad has large pieces of foam missing, or is missing entirely, it is necessary to replace it. 

To replace a skid pad, first remove what remains of the old one. Remove the gaffer’s tape around the edge, if 

present. Forcibly pull the skid pad material off as thoroughly and cleanly as possible. Use a flathead screwdriver or 

rounded-tip knife to scrape away any remaining foam, tape, or glue. Paint may be scraped but the Kevlar skin will 

remain resilient as long as it is not cut.

Adhere gaffer’s tape to the flat side of the skid pad. Use the tape to bend the pad such that it matches the 

curvature of the fuselage. Trim any excess tape. 

 

Left: Gaffer’s tape applied to the flat side of a replacement skid pad. Note how the tape holds a bend in the pad. 

Right: Skid pad with trimmed Gaffer’s tape.

Attach the replacement skid pad using a hot glue gun. Apply hot glue around the perimeter of the skid pad and 

attach it to the aircraft making sure it conforms to the fuselage. Apply pressure to the pad until the glue has 

cooled. Finally, add gaffer’s tape around the edges of the skid pad.
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Front skid pad attached and seamed with gaffer’s tape.

Repairing Wing Delamination

If the Kevlar skin on the wings or stabilator begins to lift or delaminate from the underlying foam, it should be 

repaired. Delamination typically occurs near a wing’s rib and at the corners of the trailing edge. 

When in the field, use gaffer’s tape to pinch down the Kevlar skin until a repair can be performed. 

Left: Gaffer’s tape around the trailing edge. Right: Gaffer’s tape removed showing delamination.

To repair the wing, pull back the lifted Kevlar skin and apply a foam safe glue (i.e. polyurethane) or epoxy to the 

exposed foam. Smear the glue with a paper towel until a light film evenly covers the foam. 
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Left: Kevlar skin pulled back exposing wing foam. Right: Gorilla Glue being applied beneath the Kevlar.

Apply gaffer’s tape or masking tape to the glued area. The tape is used to clamp down the lifting skin and to 

minimize the amount of glue that may seep between the Kevlar weave (important for glues that expand). 

Additional clamps or weight may be used for stronger adhesion.

The wing is taped and clamped until dry.

Once dry, remove the tape and peel away or sand any remaining glue.
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Re-Binding the DX7s Transmitter 

The binding procedure is used to pair a Spektrum transmitter with a Spektrum receiver. A ready to fly Lynx ships 

with radios already bound. This walkthrough is intended for users who choose to integrate their own electronics. 

1. Turn the aircraft off by disconnecting the battery. 

2. Press the roller button on the DX7s to enter the Setup menu. Scroll down to Servo Setup and press the 

button. Change the first item to Servo Travel, second item to Aux 1, and third item to 100 100. Press Back 

twice to exit the Setup menu.

3. Turn off the DX7s transmitter.

4. Insert the bind plug into the Spektrum receiver port labeled “Bind/Data.”

5. Ensure the throttle key is inserted, and turn the aircraft on by connecting the battery. The receiver in the 

autopilot bay should rapidly flash orange.

6. Remove the bind plug. 

7. On the DX7s transmitter, flip the autopilot switch to Auto. Press and hold the black button on the top left 

of the radio. 

8. Turn the DX7s transmitter on. The screen will say Binding. 

9. As soon as the screen says Transmitting, release the black button on the top left of the radio. 

10. Wait until the DX7s transmitter has finished binding and beeps before releasing the sticks. The receiver 

lights should now be solid orange. Move the mode switch to manual and confirm the correct movement 

of the flight surfaces. If the flight surfaces do not respond or the light is not solid then repeat the binding 

process.

11. Enter the Servo Setup menu again, and reduce Aux 1 servo travel back to 43 100. Press back twice to exit 

the menu. 

12. Test autopilot switch functionality. 

13. Test RTL functionality by turning off the DX7s transmitter and observing the flight modes on a laptop GCS. 
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Appendix I

ESC Beep Codes

ESC beeps notify status and/or errors of the propulsion system. The ESC code table is reproduced from page two of 

the Castle Edge Manual (P/N: 095-0176-00 revised 03/2013). 

(*) Repents a short beep (–) represents a long beep

Tone Meaning Description

“Castle Power” 

tune with beeps 

corresponding to 

number of cells

Power up notice ESC plays Castle signature tone and beeps out the number of cells 

attached to controller. Note: when Auto-LiPo detection is disabled by the 

user, ESC will not beep the number of cells. ESC will not run motor until it 

receives an arming signal from the radio via the throttle lead

Arming Tone ESC ready to run 

motor

ESC plays the Castle arming tune once it receives a signal from the 

receiver. Controller is ready to run the motor at this point.

* Powered ESC 

notice

ESC beeps motor every 10 seconds to remind user that power is 

connected to the ESC. This notice may be disabled in Castle Link.

*- Low Voltage 

Cutoff

Main battery voltage dropped below the cutoff value. The default is AutoLiPo which sets the cutoff value based on the detected cell count. Other 

settings may be entered in Castle Link

*-* Over Temperature ESC reached an overtemp condition. Occurs when operated under too 

high a load or operated without proper cooling airflow

*-- Excessive Load ESC detected very high current spikes. Causes may include damaged 

wiring leading to, or inside, the motor, or the use of too large a motor for 

the controller.

Remove power from the controller and check for shorts. If none are found, 

verify the controller can handle the motor’s current load. As a safety 

feature, if multiple Excessive Load errors are detected, beeping will be 

disabled.

If error continues, contact Castle Tech Support.

** Start Fail ESC was unable to start motor

**- Radio Glitch ESC detected unusual signals or loss of signal on throttle wire.

*** Motor Anomaly ESC detected a sudden interruption of the motor’s rotation.

-* Over-Current ESC detected operating currents that exceed the cutoff value.

-** AUX Wire Glitch ESC detected unusual signals or loss of signal on the AUX line.
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Appendix II

Battery Cell Discharge Curve 
AFM 2-4

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Appendix III

Lynx M PWM/PPM Wiring Diagram 
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Appendix IV

Downloading Autopilot Logs

If for any reason you need assistance with reviewing a problem encountered with a flight, preflight, or 

configuration, there are two logs that you will typically be asked to provide. The first is the autopilots log, which is 

stored on the autopilot. The second is the ground station’s log, which is stored on your GCS device.

To download the autopilot log, simply remove the SD card from the autopilot, open it on any computer and find 

the APM/LOGS folder. This folder will contain all the log files from the autopilot. Typically the log you would be 

looking for is the most recent log file, which would be the highest number. If not you can try looking at the size and 

date created to determine which one you need. Copy the .bin file from the micro SD card and send that to 

Support@swiftradioplanes.com. Do not forget to reinsert the micro SD card into the autopilot before powering on.

To download the log from Mission Planner, you can select the Config/Tuning tab in Mission Planner and on the 

Planner tab you can find the path where Mission Planner stores the logs. Within that folder the telemetry logs will 

be stored within the FIXED_WING/1 folder. Find the appropriate date/time for the log file and send the .tlog and 

.rlog files. (If you are unsure you can send all the files that have the same name).